4,4’- (Diazoamino) -dibenzenesulfonic acid (DAADBSA) has been found in samples of FD&C Yellow No. 6 that were submitted for certification. The material was detected by conventional elution chromatography and highpressure liquid chromatography (HPLC). DAADBSA is synthesized by diazotizing sulfanilic acid. The diazonium compound is then coupled with undiazotized sulfanilic acid in the presence of sodium acetate. A method for the quantitative determination of DAADBSA in FD&C Yellow No. 6 using HPLC is presented. An untested method of correcting for interfering compounds is also described.

Background Paradoxical adipose hyperplasia (PAH), a rare side effect of CoolSculpting (cryolipolysis), is characterized by fatty enlargement of the treatment area occurring months after the procedure. Objectives The purpose of this study is to report a retrospective case series of patients diagnosed with PAH at our institution, increase the collective understanding of this complication and subsequent management, and raise the question of who should ethically perform cryolipolysis. Methods All participants diagnosed with PAH by a plastic surgeon at a large academic medical center were identified. Demographic information, medical history, procedure details, time to PAH diagnosis, and corrective surgical intervention details were collected. Mean duration of time from cryolipolysis treatment to diagnosis of PAH was calculated, along with other descriptive statistics. A scoping review of all PAH literature published in PubMed, Embase, and Web of Science was also conducted. Results Four patients diagnosed with PAH after cryolipolysis were identified for inclusion in this study. The calculated incidence of PAH at our center was 0.67%. All patients requested therapy for PAH and subsequently underwent either liposuction, abdominoplasty, or both. The mean duration of in-person follow-up time after final surgical treatment of PAH was 13.8 ± 19.8 months (range: 2.8-43.5). Fortunately, no patients showed signs of PAH recurrence, and three out of four patients did not show signs of residual deformity. Conclusions Findings from this patient cohort and scoping review provide evidence that although revisions may be required, conventional body contouring methods, not in the armamentarium of non-plastic surgeon practitioners, effectively alleviated PAH.

The statistical methods of regression analysis are applied to calibration data obtained by high pressure liquid chromatographic analysis for the intermediates and side reaction products of FD&C Yellow No. 5 and the former FD&C Red No. 2. Equations are presented which allow calculation of the regression line equation, correlation coefficient, the upper prediction limit on the blank (YUB)? t n e limit of detection in terms of concentration (XLD), response above which quantitation is performed (YQ) , and prediction intervals for a specific response. The HPLC methods for FD&C Yellow No. 5 and the former FD&C Red No. 2 are evaluated based on those calculations.

A reverse phase liquid chromatographic (LC) method is presented for determining intermediates, subsidiary colors, and 2 reaction by-products in FD&C Yellow No. 6. Gradient elution from 0.02M ammonium acetate to 60% methanol in 0.02M ammonium acetate is performed on a C-8 column. Recoveries of the analytes from samples of FD&C Yellow No. 6 were as follows: 82 to 129% for the intermediate sulfanilic acid added at levels ranging from 0.04 to 0.2%; 85 to 107% for the intermediate Schaeffer's salt added at levels ranging from 0.03 to 0.3%; 91 to 107% for the reaction by-product 4,4'-(diazoamino)-dibenzenesulfonic acid added at levels ranging from 0.01 to 0.1%; 67 to 108% for the reaction by-product 6,6'-oxybis(2-naphthalenesulfonic acid) added at levels ranging from 0.1 to 1%; 88 to 100% for the subsidiary color 3-hydroxy-4-[(4-sulfophenyl)azo]-2,7-naphthaIenedisulfonic acid added at levels ranging from 0.7 to 5%; and 43 to 106% for the subsidiary color 6-hydroxy-5-(phenyIazo)-2-naphthalenesulfonic acid added at levels ranging from 0.1 to 1 %. To further demonstrate the capabilities of the method, results of multiple analyses of several FD&C Yellow No. 6 samples are presented, and results from corresponding analyses by an AOAC ion exchange LC method and by a thin layer chromatographic method are compared with results found with the new reverse phase LC method.